6-Thioguanine (6-TG) is a thio analog of the purine base guanine that incorporates into DNA during replication, inducing double-strand breaks that destabilize its structure and result in cytotoxicity. Upon incorporation into DNA, 6-TG has been shown to disrupt cytosine methylation by DNA methyltransferases, interfering with the epigenetic pathway of gene regulation. This compound has been used as a chemotherapeutic for acute leukemia and other types of cancer, including BRCA2-mutated tumors.
